An alicyclic structure-containing polymer that is produced from a norbornene-based monomer (e.g., dicyclopentadiene) using a normal production method is an amorphous resin that does not have a melting point. A crystalline resin that has a melting point can be obtained by subjecting dicyclopentadiene to ring-opening polymerization using a specific catalyst, and hydrogenating the carbon-carbon double bonds included in the resulting ring-opening polymer.
Patent Documents 1 and 2 disclose that a hydrogenated dicyclopentadiene ring-opening polymer (i.e., crystalline resin) can produce a film that exhibits excellent heat resistance, excellent flatness, and low water absorption, and can be used in various fields.
Patent Document 3 discloses that a stretched film obtained by stretching a film formed of an amorphous alicyclic structure-containing polymer produced from a norbornene-based monomer is suitable as an optical film.
A film formed of an amorphous alicyclic structure-containing polymer is normally stretched at a temperature higher than the glass transition temperature.